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City building permits

City of O'Fallon

How to apply for a building permit in City of O'Fallon, Missouri. Permit authority, application steps, fees, and inspection requirements.

Last verified
April 2026
On this page 6
§ 01

Permit authority

City of O'Fallon Planning and Development Department

Street address
100 North Main St., O'Fallon, MO 63366
Coverage
Applies within the City of O'Fallon municipal limits in St. Charles County.
Online portal
City Website
Additional resources
§ 02

When a permit is required

Permit triggers and exempt work for O'Fallon

New construction, additions, remodels, accessory structures, many trade permits, and other regulated work under city code.

Note: No consolidated public exemption list was located on the public pages reviewed.

Required documents
  • Permit form
  • Plans and specifications
  • Site plan or plat information as applicable
  • Contractor data
  • Project valuation
Building code
City enforces locally adopted construction codes; exact edition should be confirmed from city ordinance before application.
Contractor requirements
City administers contractor licensing and registration tied to permit issuance.
§ 03

Application process

Application → plan check → issuance → inspection → final

  1. 01
    Verify permit type with Planning and Development and check for zoning, engineering, or right of way reviews.
  2. 02
    Prepare permit application, plans, and contractor information.
  3. 03
    Submit through the City permit process.
  4. 04
    City completes review and returns comments if revisions are required.
  5. 05
    Fees are paid after approval.
  6. 06
    Permit is issued and inspections are scheduled with the City.

Source: City of O'Fallon Planning and Development Department ↗

§ 04

Fee schedule

O'Fallon building permit fees

Fee type
Amount
01
Permit fee formula
Mix of valuation-based and permit-type specific fees.

Paid through the City permit process.

Fees change periodically. Confirm at the official fee schedule ↗ before budgeting.

§ 05

Required inspections

Scheduling and sequence

How to schedule
  • City after permit issuance (phone)

Typical sequence: Footing/foundation, rough framing and trades, then final inspections.

§ 06

Frequently asked

Common questions about O'Fallon permits

01 Do I need a building permit in O'Fallon, MO?
New construction, additions, remodels, accessory structures, many trade permits, and other regulated work under city code.
02 How much does a building permit cost in O'Fallon, MO?
Building permit fees in O'Fallon, MO are set by the local building department and vary by project type and valuation. Fees are calculated as: Mix of valuation-based and permit-type specific fees..
03 How do I apply for a building permit in O'Fallon, MO?
To apply for a building permit in O'Fallon, MO, follow these steps: 1. Verify permit type with Planning and Development and check for zoning, engineering, or right of way reviews. 2. Prepare permit application, plans, and contractor information. 3. Submit through the City permit process. 4. City completes review and returns comments if revisions are required. 5. Fees are paid after approval. 6. Permit is issued and inspections are scheduled with the City.
04 How do I schedule a building inspection in O'Fallon, MO?
Once your permit is issued and work reaches an inspection milestone, you can schedule a building inspection in O'Fallon, MO via: City after permit issuance.
last verified April 2026 source City of O'Fallon Planning and Development Department ↗ entry id permits/missouri/st-charles/ofallon

Educational reference. Permit rules and fees change — confirm current requirements directly with City of O'Fallon Planning and Development Department before applying. Jaspector is not legal advice.